Semiconductor devices, such as ASICs, have traditionally been manufactured by ASIC design and fabrication houses having both ASIC design and fabrication capabilities. Recently, however, the design and fabrication functionalities have become bifurcated, such that a customer may bring his fabready design to a fabrication house, having no design capability. The customer may employ conventionally available cell libraries, such as those available, for example, from Artisan or Mentor Graphics together with known design rules, to design their own devices.
Semiconductor design modules having specific functions, known as cores, are also available for integration by a customer into his design. An example of a commercially available core is a CPU core, commercially available from ARM Ltd. of Cambridge, England.
Cores may be provided in a variety of forms. For example, a "soft core" may be in the form of a high level schematic, termed RTL, while a "hard core" may be at a layout level and be designed to specific fabrication design rules.